Work-Related Stress Questionnaire: confirmatory factor analysis for construct validation by the PHRASI study.

OBJECTIVE: The purpose of this study is to validate the 13-item version of the Work-Related Stress Questionnaire (WRSQ) on a representative sample of Italian public health residents. MATERIALS AND METHODS: The WRSQ was administered as part of the Public Health Residents' Anonymous Survey in Italy (PHRASI) from 14 June to 26 July 2022. Collinearity between each questionnaire item was assessed with Kendall's τ statistic. The latent factors identified associating similar items based on the authors' observations were workplace, job demand, support and unpleasant workplace. Goodness-of-fit was assessed with confirmatory factor analysis calculating: Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), Root Mean Square Error of Approximation (RMSEA), Standardized Root-Mean-Residual (SRMR). Cronbach's alpha (α) and Omega McDonald (ω) were calculated to evaluate the reliability of the questionnaire. R 4.2.2 was used to perform the analyses. RESULTS: 379 Public Health residents (58% women) responded to the questionnaire. No significant collinearity was found between the items (τ range -0.31 to 0.49). Confirmatory Factor Analysis showed CFI = 0.975, TLI = 0.967, RMSEA = 0.041 and SRMR = 0.051. Internal consistency of the WRSQ Total Score was α = 0.80 and ω = 0.85. CONCLUSIONS: Although validated in a sectorial subpopulation of healthcare workers, the WRSQ proved to be an excellent tool for assessing work-related stress. Unpleasant workplace latent factors showed lower factor loading and internal consistency than others. This could be due to the fact that topics investigated with unpleasant workplace items (e.g., abuse and discrimination) are experienced on a less regular basis than the ones assessed through the other items.

Menstrual changes after COVID-19 vaccine administration: a systematic review.

OBJECTIVE: During the mass vaccination campaign for COVID-19, cases of menstrual cycle changes in women emerged, so it was thought that the COVID-19 vaccine could affect the menstrual cycle. Over time, these observations have become more frequent, which strengthens the idea. This systematic review aims to show changes in the menstrual cycle after COVID-19 vaccination. MATERIALS AND METHODS: This study was carried out following the guidelines of the Cochrane Collaboration and the Meta-analysis of Observational Studies in Epidemiology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes. RESULTS: A suitable bibliography on PubMed/Medline and Scopus was searched by combining text, words, and titles of medical topics. After completing the search, a total of 42 articles were included in this systematic review. CONCLUSIONS: The COVID-19 vaccines may have an impact on the quality of life of women. The changes in the menstrual cycle tend to resolve within 2-3 months of vaccination and the symptoms are mild to moderate and tend to self-limit over time.

Extra-auditory effects of noise exposure in school workers and preventive measures: a systematic review.

OBJECTIVE: Noise is still today one of the main causes of occupational diseases; in fact, in Italy in the three-year period 2019-2022, hearing loss represented 15% of all occupational diseases recognized by the National Institute for Insurance against Accidents at Work. The extra-auditory effects related to noise exposure also require particular attention, because they can interfere with mental activities that require concentration, memory and ability to deal with complex problems, causing sleep and learning disorders. For this reason, acoustic comfort is considered a fundamental requirement for obtaining an optimal degree of well-being in closed environments. In schools, a high degree of noise pollution not only makes it difficult for students to listen and learn, but also affects school workers. The aim of this study was to perform a systematic review of international literature and analysis of the preventive measures of extra-auditory effects among school workers. MATERIALS AND METHODS: The presentation of this systematic review is in accordance with the PRISMA statement. The methodological quality of the selected studies was assessed with specific rating tools (INSA, Newcastle Ottawa Scale, JADAD, JBI scale and AMSTAR). Only publications in English were selected. No restrictions were applied for the publication type. We excluded articles not concerned with the extra-auditory effects of noise exposure in school workers and preventive measures, findings of less academic significance, editorial articles, individual contributions, and purely descriptive studies published in scientific conferences. RESULTS: Online research indicated 4,363 references: PubMed (2,319), Scopus (1,615) and Cochrane Library (429) have been consulted; 30 studies were included in this review (5 narrative or systematic reviews and 25 original articles). Regarding the scores of narrative reviews, the INSA score showed an average and a median value of 6.5, thus indicating an intermediate/high quality of the studies. Regarding the scores of systematic reviews, the AMSTAR score showed an average of 6.7 and a median and a modal value of 6, thus indicating a high quality of the studies. The scores assigned to the original articles have an average and median value of 7 and a modal value of 6 and this demonstrates an intermediate/high quality of the studies. CONCLUSIONS: We can assume that, as it is highlighted by this study, to date these consequences are not considered at the legislative level for the protection of exposed workers. The extra-auditory effects impacting health afterward environmental noise exposure are many and widespread. Therefore, there is a need for interventions to be carried out by institutions and that the physician of the schools, during health surveillance, investigates the effects and clinical manifestations, in order to prevent disorders and deficits highlighted by our study.

Predictive comorbidities of hospital admission in 1,571 SARS- CoV-2 positive patients: analysis of administrative data from an Italian Local Health Autority.

Purpose: Globally, age and some comorbidities have been associ-ated with the risk of more severe outcomes of COVID-19. The purpose of this research is to calculate the hospitalization rate of SARS-CoV-2 positive patients in an Italian Local health Authority (LHA) and to examine whether medical comorbidities encoded through pharmaceutical administrative data are predictors of hospital admission in patients with a positive SARS-CoV-2 naso-pharyngeal swab. Methods: This retrospective observational study was conducted in a LHA of Pescara. Comorbidities were coded through the consumption of drugs, using the WHO's Anatomical Therapeutic Chemical (ATC) classification System. The admission was ascertained by checking the hospital discharge records where generated. Results: During the study period, 1571 patients were tested positive for SARS-CoV-2 oro-and-nasopharyngeal swab. Multivariable logistic analisys showed as predictors of admission an age ≥65 in the total sample (aOR 10.91; 95%CI 6.86-17.36) as well as in the male (aOR 12.64;95%CI 6.42-24.87) and female. (aOR 9.27; 95%CI 4.87-17.66) in SARS-CoV-2 positive patients. Comorbidities assiociated with admission were (GERD) in overall (AdjOR 1.58; 95% CI 1.06-2.34) and male (AdjOR 2.30; 95%CI 1.12-4.72) samples and anticoagulants drugs use in male (AdjOR 3.90; 95% 1.11-13.65) sample, the presence of congestive heart failure (CHF) in female (AdjOR 0.47;95%CI 0.27-0.83) sample results as protective factor. Conclusion: In conclusion, increasing age, male gender and PPI use are positively associated while female gender and CHF-related drug use are negatively associated with hospitalization in SARS-CoV-2 positive patients.

Pharmacists' mental health during the SARS-CoV-2 pandemic in Italy.

OBJECTIVE: The year 2020 was characterized by the outbreak of a new pandemic caused by a novel coronavirus named SARS-CoV-2. To face the pandemic, many countries worldwide imposed general lockdowns, closing all non-essential businesses. As primary care services, pharmacies had to remain open, thus putting pharmacy staff at significant risk of viral infection and overwork. This study aimed to assess the mental health of Italian Pharmacists, considering demographic and occupational characteristics, lifestyle, and habits, during the SARS-CoV-2 outbreak and the subsequent lockdown period (March-May 2020). MATERIALS AND METHODS: A web-based survey was created using Google® Forms to collect data from March 30, 2020, to June 1, 2020. The questionnaire consisted of three sections investigating: (1) demographic and occupational variables, (2) lifestyle and habits variables, (3) psychological distress and perceived well-being. RESULTS: A total of 401 participants completed the questionnaire. Older workers and those with more work experience reported more psychological stress. Older and female workers, who felt lonely at home and reported psychological stress, perceived poor well-being. CONCLUSIONS: Our findings demonstrate that the Sars-CoV-2 outbreak and subsequent lockdown rules affected pharmacists' mental health and that it is important to put in place preventive measures against the occurrence of mental disorders among them.

Total parenteral nutrition is associated with worse hospital outcomes among elderly diabetic patients: a propensity score matched analysis on discharge records.

Background: Recent trials and reviews have raised question about the safety of total parenteral nutrition (TPN), due to the increased rate of TPN related complications. Diabetic patients are vulnerable to hyperglycaemia, and poor studies have investigated hospital out-comes of diabetic patients requiring TPN. The aim of this study was to evaluate the association of in-hospital mortality, prolonged length of stay and transfer to long-term care facilities among diabetic patients with TPN. Methods: The study considered all hospital admissions of diabetic patients over 65 years of age performed between 2006 and 2015 in Abruzzo Region, Italy. To compare the outcomes of TPN and non-TPN patients, a propensity score matching procedure was performed. Results: A total of 140,556 admissions were analyzed. After matching, 1947 patients were included into the analyses: 649 patients with TPN and 1298 controls. TPN was significantly associated to in-hospital mortality (OR=7.15; 95%CI 5.54-9.22), prolonged LOS (OR=2.78; 95%CI 2.28-3.38) and transfer to LTCF (OR=2.16; 95%CI 1.64-2.85). Discussion: TPN is associated with poor outcomes among elderly diabetic patients in the Italian setting. Being aware of the risk factors among diabetic patients with TPN can be used to anticipate the patients' needs during the admission and the immediate post-discharge period.

Telework and its effects on mental health during the COVID-19 lockdown.

OBJECTIVE: During the Covid-19 pandemic, many governments promoted the adoption and development of telework to reduce some of the consequences of the current health crisis on the economy and favor social distancing. The aim of this web-based cross-sectional study was to assess the consequences of the Covid-19 pandemic on job organization, exploring the effects of lockdown measures on the psychological distress and perceived well-being of workers experiencing telework. SUBJECTS AND METHODS: A web-based cross-sectional survey has been used to collect data. The participants answered the questionnaire from April 1 to April 30, 2020. The questionnaire consisted of three sections, which investigated: 1) demographic and occupational variables, 2) lifestyle and habits variables, 3) psychological distress and perceived well-being. The General Health Questionnaire (GHQ-12) has been used to evaluate psychological distress and the 5-item World Health Organization Well-Being Index (WHO-5) to explore subjective well-being. RESULTS: Psychological distress was associated with educational level, with habits, and with reporting poor well-being. Poor well-being was associated with a higher job demand during pandemic, lifestyle and habits variables, and psychological distress. CONCLUSIONS: This is one of the first studies exploring the consequences of the COVID-19 pandemic and lockdown measures on the perceived well-being and psychological distress of workers experiencing telework. It is mandatory to pay more and more attention to the mental health of teleworkers, considering the increasing diffusion and adoption of this type of work organization.

Gender differences in childhood bmi z-score, alimentary behaviour and lifestyle in a sample of 9-11 children.

BACKGROUND: Child overweight and obesity prevalence has risen substantially in most high-income countries. The prevention of childhood overweight and obesity is a major public health issue. Childhood obesity leads to an increased risk of both physical and mental health consequences,. The aim of this study was to investigate the gender differences in BMI z-score, eating habits, life style and healthy behaviors in children. MATERIALS AND METHODS: With an approach so-called "cluster" method we selected third classes of primary schools. The study was conducted from September 2016 and May 2017 during a school year. Information was collected through a questionnaire filled in by the children with the help of their parents. The biometric data relating to height in meters and weight in kilograms was obtained through the questionnaire. RESULT: A total of 1122 children were included in the current study. 33.9% of boys being overweight compared with 27.8% of girls and 19.1% of boys being obese compared with 12.5% of girls (p<0.001). There were significant differences between boys and girls for physical activity (p=0.004), sedentary behaviors (p<0.001), eating habits (p=0.004). DISCUSSION: In this study, gender differences were analyzed with respect to BMI z-score, eating habits, life style and healthy behaviors in children between 9 and 11 years old. The results of the study confirm the differences that the scientific literature described. Between boys and girls there are different habits that on the one hand can determine differences in the quality of life and future health and on the other hand can be the key to implementing effective and targeted prevention interventions.

The impact of COVID-19 on doctors' well-being: results of a web survey during the lockdown in Italy.

OBJECTIVE: On March 12, 2020, the World Health Organization (WHO) declared the outbreak of a new Coronavirus disease (COVID-19), to be a pandemic. From the beginning, Italy (in particular the Northern regions) was the first large European country to be hit and one of the most affected countries worldwide. This had a significant impact on the workload and psychological health of health workers. The aim of this web-based cross-sectional study is to assess the consequences of the COVID-19 pandemic on Italian doctors' well-being and psychological distress, in respect of demographic and occupational characteristics, lifestyle and habits during the lockdown period. PATIENTS AND METHODS: We conducted a web-based cross-sectional survey based on Google® Forms to collect data. The participation was available during the lockdown period that started in Italy on March 9, 2020 and it was voluntary and anonymous. The questionnaire explored demographic and occupational variables, lifestyle and habits during the lockdown, perceived well-being and psychological distress. Multivariate logistic regression models were fitted. RESULTS: Our study reported the very alarming psychological conditions of Italian doctors, especially among those who worked in the most affected regions, where a level of psychological distress of 93.8% and poor well-being of 58.9% were registered. These percentages were even higher in the case of female hospital workers with low job seniority, and those caring for COVID-19 patients. CONCLUSIONS: Our findings reported a significant psychosocial impact of the COVID-19 outbreak on Italian doctors, particularly among those working in the most affected regions of the country. Further studies are necessary to better understand the effects of the COVID-19 pandemic on doctors' well-being and mental health over time, in order to implement effective prevention measures.

Work-Related Stress Questionnaire (WRSQ): a new tool to assess psychosocial risks at workplaces.

INTRODUCTION: Work-related stress (WRS) can harm both physical and mental health but it shouldn't only be considered in its negative sense. The evaluation of WRS cannot be separated from the analysis of the subjective perception of workers, usually made by questionnaires. The aim of this pre-pilot study is to identify a new questionnaire capable of exploring as many psychosocial risk domains as possible and with a high internal consistency. MATERIAL AND METHODS: A first version of the questionnaire was administered to a convenience sample selected on a voluntary basis; both socio-demographic and work-related data were collected. A single item test was conducted on a group of 50 workers in order to assess whether the questions were confusing and to understand if they could be improved. The study sample completed the questionnaire at time 1 and time 2 (after 3 days). The 33-item version of the questionnaire was web-based in Google Form. Cronbach's alpha and Pearson's r were calculated. RESULTS: The analysis of the 33-item questionnaire at time 1 shows an excellent reliability with Cronbach's alpha coefficients of 0.93. At time 2 Cronbach's alpha coefficients was 0.94. Based on the test-retest score, the items with the highest scores were selected as part of the final version of the questionnaire (10-item). The reliability of this 10-items version is high with a Cronbach's alpha coefficients of 0.86 both at time 1 and at time 2. Two items have been chosen to explore the "emotional demand" and "dealing with technology". CONCLUSIONS: The pre-pilot study provided a questionnaire with high reliability and high repeatability. In its final version, the questionnaire investigates different psychosocial risk domains and represents a possible useful tool for assessing worker's exposure to them. The Authors reserve to administer the questionnaire to a larger population.

Work-related stress risk and preventive measures of mental disorders in the medical environment: an umbrella review.

OBJECTIVE: Work-related stress (WRS) is widespread among medical doctors. WRS not only affects the physician's mental and physical well-being, but also patient care quality and the overall efficiency of the healthcare system. The aim of this study is to conduct a systematic review of the current preventive measures against mental disorders, work-related stress, and burnout among physicians. MATERIALS AND METHODS: The presentation of this systematic review is in accordance with the PRISMA statement. The methodological quality of the selected studies was assessed with specific rating tools: INSA, Newcastle Ottawa Scale, JADAD scale, and AMSTAR. English publications only were selected. No restrictions applied for publication type. Reviewers excluded articles not concerning the following topics: WRS prevention, WRS risk factors and mental disorders among physicians. Reviewers also excluded findings of less academic significance, editorial articles, individual contributions, purely descriptive studies published in scientific conferences. RESULTS: Online search returned 4748 references on the following databases: PubMed (1638), Scopus (3108) and Cochrane Library (2). 36 studies were included in this review (thereof, 13 reviews and 23 original articles). Narrative reviews were rated on the INSA scale. The mean, median, and modal rating was 6. This indicates an intermediate-high quality of these studies. Systematic reviews were rated on the AMSTAR scale. The mean and median rating was 9, and the modal rating was 8. This indicates a high quality of these studies. The scores assigned to the original articles have a mean, median, and modal rating of 7. This also indicates an intermediate-high quality of these studies. CONCLUSIONS: Work-related stress and mental disorders seem to be widespread among medical practitioners. It is already a priority to adopt preventive measures against these phenomena. However, there is still no consensus on what the most effective measures are. Additional research is needed to formulate evidence-based recommendations.

Bullying at work and work-related stress in healthcare workers: a cross sectional study.

BACKGROUND: Bullying is a serious and growing problem affecting a significant proportion of healthcare professionals, a professional category exposed to work-related stress. Workplace bullying has been defined as a set of negative behaviours consisting in harassment, offense or negative influence on work that are directed to the members of the organization and that occur regularly and repeatedly over a period, becoming part of the context of work. STUDY DESIGN: We performed a cross-sectional study using the HSE questionnaire and defining the sample size considering the number of healthcare workers of a big hospital and then calculating it with EpiInfo™ software. 191 people have been enrolled. METHODS: The study was divided into three steps. The first one to identify, among the workers, those who were exposed to bullying at work and those who were not. The second one has been aimed at assessing the presence of work-related stress through the administration of the HSE questionnaire. The third step has been aimed at performing the statistical analysis of the data. For each single domain explored by the questionnaire the score obtained was treated as a linear variable and the median and interquartile range (IQR) was calculated. After, a non-parametric analysis (Wilcoxon rank-sum test) was performed in order to define the statistical significance of the observed differences. RESULTS: All the 191 questionnaires were self-administered by the Health Care Workers under study and correctly filled in without any multiple or missing responses. Considering the scores obtained to question n. 21, that investigates "bullying at work", we obtained two groups: High-Exposure Group (total, males and females), and Low-Exposure Group (total, males and females). In the High-Exposure Group, two critical domains were found: Demands and Control (total, male and female samples). The differences with the Low-Exposure Group were statistically significant. In the Low-Exposure Group the critical domain was Manager Support (total and female samples). The differences with the High Exposure Group were not statistically significant. CONCLUSION: This study aimed to show how the exposure to bullying can influence the perception of psychosocial risks. It seems that the workers most exposed to bullying also have worse scores on the HSE questionnaire, particularly for two domains: Demands and Control. That is consistent with the most recent scientific literature.

Predictors and Trend of Ketoacidosis Hospitalization Rate in Type 2 Diabetes Mellitus Patients from 2006 to 2015 in Abruzzo Region, Italy.

AIMS: This study aimed to assess the trend of hospitalizations for DKA in adult patients with type 2 diabetes mellitus and its associated factors. DESIGN: A retrospective cross-sectional study was performed. Data were collected from hospital discharge records (HDRs) of patients (age ≥18) with either primary or secondary discharge diagnosis for DKA and type 2 diabetes from 2006 to 2015 in Abruzzo region. Age-adjusted hospitalization rates were computed by gender and standardized on the regional population in 2006. A logistic regression model was implemented using presence of DKA as dependent variable. RESULTS: We identified 160,366 HDRs with type 2 diabetes. Out of them, 1611 (1.00%) were due to DKA. The hospitalization rates for DKA increased both for male +115.9 and female +142.8%, from 2006 to 2015. The most significant predictors of DKA were age 18-44 (aOR=4.17), uncontrolled diabetes (aOR=1.79), trauma (aOR=1.38), any infection (aOR=1.68), liver disease (aOR=1.29), fluid and electrolyte disorders (aOR=2.09), psychosis (aOR=1.69). CONCLUSIONS: Trends of DKA in adult patients with type 2 diabetes has been increasing in both male and female. Multimorbidity is an open challenge for public health, therefore better coordination is needed among different specialist consultants to reduce the occurrence of this preventable complication.

Work-related stress and cortisol levels: is there an association? Results of an observational study.

OBJECTIVE: Chronic exposure to work-related stress (WRS) stimulates the hypothalamic-pituitary-adrenal (HPA) axis to increase glucocorticoid secretion, including cortisol, and these hormones can be measured both in serum and urine. The Health Safety Executive Toolkit (HSE) questionnaire is used to assess WRS risk objectively. The scope of our study is to investigate whether serum or urinary cortisol levels could be used as alternative objective indicators of WRS, specifically in those subjects who are chronically exposed to it. PATIENTS AND METHODS: 130 patients (75 males and 55 females, mean age 47.7 ± 11.3 years) were evaluated at a specialized Centre for Secondary Hypertension, where both their serum (8 AM) and 24-hours urinary cortisol were measured and they were asked to complete two questionnaires: one questionnaire to collect data about their socio-demographic and job characteristics, and the HSE questionnaire to evaluate WRS. RESULTS: Multiple linear regression analysis showed an association of urinary cortisol with several variables: tobacco smoke (ß = 69.6; p = 0.003); female gender (ß = -37.3; p = 0.041); exposure to physical risks (ß = 51.8; p = 0.032); control score (ß = -22.7; p = 0.039); role score (ß= 39.3; p = 0.020). Age was the only variable associated with serum cortisol levels (ß = -3.6; p = 0.042). CONCLUSIONS: Urinary cortisol levels, but not serum levels, are associated with variables linked to WRS (score control and role) and to socio-demographic variables, namely gender and tobacco smoke. Thus, urinary cortisol can be considered a useful and non-invasive biological indicator to quantify WRS.

The perception of psychosocial risks through the HSE questionnaire of a population of neurophysiology technicians: a cross-sectional study.

OBJECTIVES: The Neurophysiopathology Technicians (NTs) are exposed to psychosocial risks, exposure to psychosocial risks that cause related work stress has been related to numerous physical and mental illnesses. The aim of this study is to evaluate the perception of psychosocial risks in a population of this population. MATERIALS AND METHODS: 54 technicians of Neurophysiopathology were enrolled, consisting of 23 males (42,6 %) and 31 females (57,4 %). All subjects were administered the HSE questionnaire developed by the Health and Safety Executive. the statistical analysis provided for the assessment of the reliability of the questionnaires and the non-parametric analysis of gender differences. RESULTS: In the total population emerges as critical the perception of the domain "Managers' Support" with Cronbach's alpha values for total males and females respectively of 0,87, 0,85, 0,88. In the female population is added the critical perception of the "Peer Support" domain (p=0,026), shows that the employees indicated that they do not receive adequate information and support from their colleagues. DISCUSSION: The study highlights the exposure to psychosocial risks by technicians of neurophysiopathology able to mediate the phenomenon of WRS. The HSE questionnaire represents a tool capable of highlighting specific risks to which workers are exposed. Furthermore, its ability to capture elements of the work context significantly increases if an analysis is carried out that takes into account the worker's gender.

Job stress: an in-depth investigation based on the HSE questionnaire and a multistep approach in order to identify the most appropriate corrective actions.

BACKGROUND: Psychosocial hazards and work-related stress have reached epidemic proportions in Europe. The Italia law introduced in 2008 the obligation for Italian companies to assess work related stress risk in order to protect their workers' safety and health. The purpose of our study was to propose an accurate measurement tool, using the HSE indicator tool, for more appropriate and significant work-related stress' prevention measures. METHODS: The study was conducted on 204 visual display unit (VDU) operators: 106 male and 98 female. All subjects were administered the HSE questionnaire. The sample was studied through a 4 step process, using HSE analysis tool and a statistical analysis, based on the odds ratio calculation. RESULTS: The assessment model used demonstrated the presence of work related stress in VDU operators and additional "critical" aspects which had failed to emerge by the classical use of HSE analysis tool. DISCUSSION: The approach we propose allows to obtain a complete picture of the perception of work-related stress and can point out the most appropriate corrective actions.

Colorimetric assays for quantitative analysis and screening of epoxide hydrolase activity.

Focusing on directed evolution to tailor enzymes as usable biocatalysts for fine chemistry, we have studied in detail several colorimetric assays for quantitative analysis of epoxide hydrolase (EH) activity. In particular, two assays have been optimized to characterize variants issued from the directed evolution of the EH from Aspergillus niger. Assays described in this paper are sufficiently reliable for quantitative screening of EH activity in microtiter plates and are low cost alternatives to GC or MS analysis. Moreover, they are usable for various epoxides and not restricted to a type of substrate, such as those amenable to assay by UV absorbancy. They can be used to assay EH activity on any epoxide and to directly assay enantioselectivity when both (R) and (S) substrates are available. The advantages and drawbacks of these two methods to assay EH activity of a large number of natural samples are summarized.

Tailoring new enzyme functions by rational redesign.

Site-directed mutagenesis is still a very efficient strategy to elaborate improved enzymes. Recently, advances have been made in developing rational strategies aimed at reshaping enzyme specificities and mechanisms, and at engineering biocatalysts through molecular assembling. These knowledge-based studies greatly benefit from the most recent computational analyses of enzyme structures and functions. The combination of rational and combinatorial methods opens up new vistas in the design of stable and efficient enzymes.

Monitoring tissue elimination of fluorescein with the perfusion fluorometer: a new method to assess capillary blood flow.

Visual assessment of tissue staining after intravenous fluorescein is a common technique for predicting viability of questionably perfused tissue. The development of the perfusion fluorometer has permitted quantification of tissue fluorescein, providing increased precision. This study employed this instrument to calculate fluorescein elimination from rats with and without raised dorsal pedicle flaps. Control animals exhibited homogeneous patterns of fluorescein elimination consistent with first-order kinetics. Elimination in experimental animals was assessed after the animals received full back skin flaps with the cephalad pedicle remaining intact. Three distinct patterns of elimination were noted in each flap. In the cephalad portion, elimination was similar to control. At the caudad end, no elimination was noted. Midflap, fluorescein was eliminated slowly. These elimination patterns predicted ultimate viability 14 days postoperatively, as they correspond to viable, dystrophic, and transitional sections, respectively (P less than 0.001). We conclude that perfusion fluorometry can assess capillary flow in healthy and ischemic tissue by documenting elimination as well as delivery of fluorescein.